JP6729247B2 - Non-coaxial laser radar device - Google Patents

Description

The present invention relates to a non-coaxial laser radar device, and more particularly to a technique for detecting an object at a close range.

A non-coaxial laser radar device is known as a type of laser radar device. Patent Document 1 discloses an example of a non-coaxial laser radar device. The non-coaxial laser radar device is provided with a light emitting mirror and a light receiving mirror separately, and the light emitting axis which is the optical axis of the laser light projected from the laser radar device to the outside and the light receiving mirror to the outside of the device. The light-receiving axis, which is the central axis of the light-receiving field of view, is at a position different from each other.

JP, 2016-45051, A

In the non-coaxial laser radar device, the light receiving mirror is generally designed so as to guide the reflected light incident on the light receiving mirror in parallel to the projection axis to the light receiving element.

Strictly speaking, the reflected light incident on the light receiving mirror is not parallel to the light projecting axis due to the difference in position between the light projecting mirror and the light receiving mirror. However, as the distance from the laser radar device to the object is larger than the difference between the positions of the light emitting mirror and the light receiving mirror, the angle difference between the incident angle of the reflected light on the laser radar device and the light emitting axis becomes smaller. .. Further, since the light projecting mirror and the light receiving mirror are housed in one device, the difference in position between the light projecting mirror and the light receiving mirror is not so large.

Therefore, it can be considered that the reflected light generated in many distance ranges of the object detection distance range of the laser radar device is incident on the light receiving mirror parallel to the projection axis. Therefore, by designing the light receiving mirror so that the reflected light that enters in parallel with the projection axis is guided to the light receiving element, the reflected light generated in many distance ranges can be efficiently guided to the light receiving element.

However, when an object exists in a close range of the laser radar device, the reflected light generated by the object has a large angle difference with respect to the projection axis. If the angle difference with respect to the projection axis is large, the traveling direction after being deflected by the light receiving mirror does not become the direction of the light receiving element. Therefore, the reflected light generated by the object existing at a close range does not enter the light receiving element even if it is reflected by the light receiving mirror. In the following, the closest distance means a distance so short that the reflected light reflected by the light receiving mirror does not enter the light receiving element.

Since the maximum intensity component of the reflected light generated by an object existing at a close range does not enter the light receiving element even when reflected by the light receiving mirror, the following method for detecting an object located at a close range of the laser radar device is described below. A method can be considered. That is, in the time zone in which the reflected light generated at a close range is received, a method of increasing the light receiving gain so that the reflected light in a direction other than the maximum intensity can be detected can be considered.

However, in this method, it is necessary to increase the light receiving gain immediately after irradiating the laser beam and then once reduce the light receiving gain. The reason why it is necessary to lower the light receiving gain is that if the light receiving element detects a component of the maximum intensity direction of the reflected light that occurs at a distance that is slightly farther than the closest distance, the light receiving intensity is strong, so the light receiving sensitivity is high. This is because it is necessary to prevent saturation. Then, once the light receiving gain is lowered, the light receiving gain is gradually increased with the lapse of time. This is because the received light intensity decreases as the distance to the object increases. Therefore, this method has a problem that the control becomes complicated.

The present invention has been made based on this situation, and an object of the present invention is to be able to detect reflected light generated by an object located at a close range and to suppress complicated control. Another object is to provide a non-coaxial laser radar device.

The above objective is achieved by a combination of features described in independent claims, and the subclaims define further advantageous embodiments of the invention. The reference numerals in parentheses in the claims indicate the correspondence with the specific means described in the embodiments described below as one aspect, and do not limit the technical scope of the present invention. ..

The present invention for achieving the above object comprises a light source (11) for generating a laser beam,
A light projecting mirror (14) for deflecting the laser light generated by the light source, projecting the light to the outside, and scanning the light projecting direction;
A light receiving element (22) for receiving the reflected light generated by the laser light projected by the light projecting mirror being reflected by an external object,
A light receiving mirror (21) for deflecting the reflected light toward the light receiving element ,
A window (3) through which the laser light projected by the projection mirror and the reflected light pass ,
The light receiving element is above the light receiving mirror,
A non-coaxial laser in which a projection axis (Lc), which is an optical axis of laser light projected to the outside, and a light receiving axis (Rc), which is a central axis of a light receiving field extending from the light receiving mirror to the outside, are different from each other. A radar device,
By opening the side of the light receiving mirror and extending from the periphery of the light receiving element to the direction of the light receiving mirror to enclose the space on the side of the light receiving mirror of the light receiving element, light different from the reflected light reflected by the light receiving mirror enters the light receiving element. A shield (23, 223, 323) that suppresses
Shield, at least for part of the scan direction, the outer surface, away from the window, and extends downwardly along the window, close range inside surface (24b, 224b, 324b) is, that defines Me pre The direct incident boundary line (B), which is a straight line connecting the point farthest from the light receiving element in the light emitting spot generated by irradiating the object located at It is formed outside the light receiving field of the device.

In the present invention, the reflected light that directly travels from the object located at the closest distance to the light receiving element enters the light receiving element. Since the reflected light goes in various directions other than the maximum intensity direction, the reflected light has a component that goes directly to the light receiving element. If the object is located at a close range, even the component of the reflected light from the object in the direction deviated from the maximum intensity direction has relatively strong reflected light intensity. Therefore, if the reflected light that directly goes to the light receiving element from the object located at the closest distance is detected, the complicated light receiving gain control can be suppressed.

However, a shield is provided around the light receiving element. The shield allows the reflected light deflected by the light receiving mirror to enter the light receiving element, while suppressing the light other than the reflected light deflected by the light receiving mirror, that is, disturbance light, from entering the light receiving element. It is provided. Therefore, the shield has a structure that extends from the periphery of the light receiving element toward the light receiving mirror to enclose the space on the light receiving mirror side of the light receiving element, and is open on the light receiving mirror side.

With this shield, it is possible to prevent the detection-free reflected light generated outside the device from directly entering the light-receiving element, such as the reflected light generated by reflecting the laser light in a puddle, and It is also possible to suppress the internally reflected light generated inside the device from entering the light receiving element.

However, depending on the configuration of the shield, the reflected light generated by an object existing at a close range is also suppressed from directly entering the light receiving element.

Therefore, in the present invention, the inner surface of the shield is formed outside the light receiving field of the light receiving element with respect to the direct incidence boundary line in at least a part of the scanning direction. This direct incidence boundary line is the farthest point from the light receiving element in the light projecting spot, which is the range in which the laser beam is irradiated to the object located at the predetermined shortest distance, and the farthest point from the light projecting spot in the light receiving element. Is a straight line connecting

The light projection spot can also be considered to be a range in which reflected light is generated in an object irradiated with laser light. The straight line connecting the point farthest from the light receiving element in this light emitting spot and the point farthest from the light emitting spot in the light receiving element indicates that the reflected light generated at the light emitting spot directly enters the light receiving element. , Means the reflected light that passes closest to the light receiving mirror.

Since the shield has a structure extending from the periphery of the light receiving element in the direction of the light receiving mirror, when the shield intersects the straight line, the reflected light generated by the laser light reflected by an object located at a predetermined close distance Will not directly enter the light receiving element. Therefore, this straight line means a boundary between the reflected light that directly enters the light receiving element and the reflected light that does not directly enter the light receiving element.

Since the direct-incidence boundary line is a straight line having this meaning, if the inner surface of the shield is formed outside the light-receiving field of view rather than the direct-incidence boundary line, the laser light will be emitted from an object located at a predetermined close range. At least a part of the reflected light generated by the reflection is directly incident on the light receiving element.

In the present invention, the inner surface of the shield is formed outside the direct incident boundary line outside the light-receiving field of the light-receiving element in at least a part of the scanning direction. Therefore, in the scanning direction, the reflected light generated by the object located at the closest distance directly enters the light receiving element. On the other hand, in the scanning direction as well, the shielding body is formed while the inner surface of the shielding body is located outside the light receiving field of the light receiving element with respect to the direct incident boundary line, so that ambient light is incident on the light receiving element. It can be suppressed.

In the invention according to claim 2, the scanning range of the laser light is limited to a partial angular range in the horizontal plane,
The inner surface of the shield is formed outside the light-receiving visual field with respect to the direct incident boundary line within the scanning range of the laser light, while the inner surface is formed within at least a part of the scanning range of the laser light. The distance from the end point on the opening side to the central axis of the light-receiving field is shorter than the distance from the end point on the opening side of the inner surface formed in the scanning range of the laser light to the central axis of the light-receiving field.

According to the present invention, even outside the scanning range of the laser beam, the distance from the opening side end point of the inner side surface to the central axis of the light receiving field is determined from the opening side end point of the inner side surface within the scanning range of the laser beam. The opening of the shield is smaller than that in the case where the distance is the same as the center axis of the shield. Therefore, it is possible to prevent ambient light from entering the light receiving element.

In the invention according to claim 3, outside the scanning range of the laser beam, the inner side surface of the shield has a concave surface shape that collects the reflected light generated by the object located at the closest distance in the range including the light receiving element. There is.

Part of the reflected light generated by an object located at a close distance directly enters the light receiving element, and part of the remaining light enters the space surrounded by the shield, but does not directly enter the light receiving element. Then, the laser light is incident on the inner side surface outside the scanning range.

Here, if the distance to the object that causes the reflected light is determined, the angle at which the reflected light is incident on the inner surface outside the scanning range of the laser light can be determined. From this angle and the known position of the light receiving element, it is possible to design in advance how to make the concave shape of the inner surface collect the reflected light incident on the inner surface in the range including the light receiving element. Is.

Therefore, in the present invention, outside the scanning range of the laser light, the inner side surface of the shield has a concave surface shape that collects the reflected light generated by the object located at the closest distance in the range including the light receiving element. This makes it possible to increase the efficiency with which the reflected light that has entered the inner side surface outside the scanning range of the laser light enters the light receiving element.

1 is a schematic configuration diagram of a non-coaxial laser radar device 1 of an embodiment. It is the figure which looked at the vicinity of the crevice 24 of support 23 from the bottom. FIG. 6 is a diagram for explaining an inclination angle of an inner side surface 24b of a recess 24. It is a figure explaining the structure of the recessed part 124 of a comparative example. It is a figure which shows the vicinity of the recessed part 224 with which the laser radar apparatus of 2nd Embodiment is equipped. It is the figure which looked at the support stand 223 from the arrow VI shown in FIG. It is a figure which shows the vicinity of the recessed part 324 with which the laser radar apparatus of 3rd Embodiment is equipped.

<First Embodiment>
Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a schematic configuration diagram of a non-coaxial laser radar device (hereinafter, simply laser radar device) 1 according to a first embodiment of the present invention. The laser radar device 1 of this embodiment is fixed to a wall, floor, or ground of a building.

The laser radar device 1 has an irradiation unit 10, a light receiving unit 20, a comparator 30, a control unit 40, and the like housed in a closed space formed by a housing 2 and a window 3. Note that FIG. 1 is a view in which the housing 2 and the window 3 are cut along a vertical cross section passing through the center of the housing 2 and the window 3 in the width direction in order to show the internal structure of the laser radar device 1. Further, in the description of the present embodiment such as the comparator 30 and the control unit 40, the presence of elements that do not need to be described in the shape is indicated by a square.

The housing 2 is vertically long, and the window 3 is attached to the central portion of the housing 2 in the vertical direction. The surface of the housing 2 that faces the window 3 is the back surface 2a. The laser radar device 1 is installed so that the bottom surface 2b is on the lower side and the upper surface 2c is on the upper side. In addition, in the installed state, the laser radar device 1 is installed so that the upper surface 2c is located vertically above the bottom surface 2b. The direction from the rear surface 2a toward the window 3 is the front direction of the laser radar device 1. Also in the description of the present embodiment, the front direction is the Z-axis direction, the vertical direction is the Y-axis direction, and the direction orthogonal to the Z-axis and the Y-axis is the X-axis direction, according to a general expression in the optical field.

The laser radar device 1 scans the irradiation light L while irradiating the irradiation light L to the outside of the device with the front direction as the scanning center. Then, by receiving the reflected light R generated by the irradiation light L being reflected by the object, the object existing in the object detection range set around the laser radar device 1 is detected.

The window 3 is colored transparent or colorless transparent, and when combined with the housing 2, forms a closed space inside.

The irradiation unit 10 includes a light source 11, a drive unit 12, a lens 13, and a light projecting mirror 14. The light source 11 is a laser diode or the like and outputs the irradiation light L which is a pulsed laser light when a pulse current is supplied. When a command signal that commands the irradiation of the irradiation light L is input from the control unit 40, the drive unit 12 generates a pulse current and inputs the pulse current to the light source 11.

The lens 13 makes the irradiation light L output from the light source 11 into a luminous flux that is slightly diffused as the irradiation light L advances, and adjusts the size of the spot of the irradiation light L. The spot of the irradiation light L is hereinafter referred to as a light projection spot. The shape of the projected spot is circular, for example. The irradiation light L has a thickness, and the irradiation light L shown in FIG. 1 is the center of the traveling direction of the irradiation light L. The center of the irradiation light L in the traveling direction is the projection axis Lc.

The light-projecting mirror 14 is a plane mirror, is connected to the motor 15, and rotates about a substantially vertical rotation axis. The irradiation light L of which the size of the projection spot is adjusted by the lens 13 is reflected by the projection mirror 14 and is irradiated in the horizontal direction. Since the light projecting mirror 14 is rotating around the rotation axis, the irradiation light L is irradiated over a predetermined angle range in the horizontal plane. The predetermined angle range is 180 degrees in this embodiment. That is, in the present embodiment, the scanning range of the irradiation light L is limited to 180 degrees, not the entire range in the horizontal direction.

The light receiving unit 20 includes a light receiving mirror 21 and a light receiving element 22. The light receiving mirror 21 reflects the reflected light R generated by the irradiation light L reflected by an external object and guides it to the light receiving element 22. The light receiving surface of the light receiving mirror 21 is concave, and the reflected light R parallel to the light receiving axis Rc is condensed on the light receiving element 22. Here, the light receiving axis Rc is the angular range in which light is incident on the light receiving element 22, that is, the center of the light receiving field. The light receiving axis Rc is on the same line as the rotation axis of the light receiving mirror 21 between the light receiving element 22 and the light receiving mirror 21, and in the range from the light receiving mirror 21 to the outside of the device, the light receiving axis is on the rotation axis of the light receiving mirror 21. It is a straight line in the horizontal direction passing through the point P1. The direction of the light receiving axis Rc in the horizontal plane changes according to the rotation angle of the light receiving mirror 21. The light receiving mirror 21 has a rotation axis coupled to the rotation axis of the light projecting mirror 14. Therefore, the light receiving mirror 21 rotates integrally with the light projecting mirror 14.

The light receiving element 22 is, for example, an avalanche photodiode, and outputs a signal indicating the intensity of light incident on the light receiving element 22, that is, a signal indicating the light receiving intensity of the reflected light R (hereinafter, light receiving intensity signal) to the comparator 30. To do.

The light receiving element 22 is attached to the support base 23. The support 23 also functions as a shield that suppresses ambient light from entering the light receiving element 22. A recess 24 is formed in the support 23, and the light receiving element 22 is arranged on the upper bottom 24 a of the recess 24. The recess 24 has an opening on the light receiving mirror 21 side, and the inner side surface 24b of the recess 24 has a tapered shape in which the diameter increases from the upper bottom 24a, that is, the surface on which the light receiving element 22 is arranged, toward the opening in the present embodiment. Is.

The inner side surface 24b of the recess 24 extends from the vicinity of the light receiving element 22 to the light receiving mirror 21 side in the upper bottom 24a where the light receiving surface of the light receiving element 22 is located, and the space on the light receiving mirror 21 side of the light receiving element 22 is formed. Surrounded.

The comparator 30 compares the received light intensity signal with a preset detection threshold value, and continuously outputs a signal indicating a comparison result (hereinafter, a comparison result signal) to the control unit 40. There are two types of comparison result signals, a signal indicating that the received light intensity signal exceeds the detection threshold and a signal indicating that the received light intensity signal does not exceed the detection threshold.

The control unit 40 is a computer including a CPU, ROM, RAM and the like. The control unit 40 outputs a command signal for irradiating the drive unit 12 of the irradiation unit 10 with the irradiation light L, receives a comparison result signal from the comparator 30, and detects an object based on the comparison result signal. To do.

FIG. 2 is a view of the vicinity of the concave portion 24 of the support base 23 as viewed from below. As shown in FIG. 2, the opening of the recess 24 and the upper bottom 24a are circular, and the light receiving element 22 is arranged at the center of the upper bottom 24a. Further, the shape of the light receiving surface of the light receiving element 22 is also circular. The shape of the opening of the concave portion 24, the shape of the upper bottom 24a of the concave portion 24, and the shape of the light receiving surface of the light receiving element 22 may be other than circular.

As described above, the inner side surface 24b of the recess 24 is tapered so that the diameter increases toward the opening. The inclination angle of the inner side surface 24b due to this taper shape will be described below.

FIG. 3 is a diagram for explaining the inclination angle of the inner side surface 24b, and schematically shows the elements necessary for explaining the inclination angle. The inner side surface 24 b of the recess 24 is formed outside the light receiving field of the light receiving element 22 with respect to the direct incident boundary line B. In other words, the inner side surface 24b does not project to the central axis (that is, the light receiving axis Rc) side of the light receiving visual field from the direct incidence boundary line B.

The direct incidence boundary line B is a point P2 that is farthest from the light receiving element 22 in a light projection spot that is generated when the irradiation light L strikes the surface of an object (hereinafter, a short-distance object) 50 located at a close range of the laser radar device 1, In the light receiving element 22, it is a straight line connecting the point P3 farthest from the projected spot. The light projection spot generated on the surface of the very close object 50 is formed between the two irradiation lights L shown in FIG.

The light projection spot is a range in which the reflected light R is generated in the close-range object 50, and the direct incidence boundary line B is the most light receiving mirror when the reflected light R generated in the light projection spot directly enters the light receiving element 22. It is an optical path passing near 21.

Therefore, when the support table 23 directly intersects the incident boundary line B, the reflected light R generated by the close-range object 50 does not directly enter the light receiving element 22. In addition, even if the reflected light R is reflected by the light receiving mirror 21, the maximum intensity component of the distance between the close-range object 50 and the laser radar device 1, that is, the close-range distance in this embodiment, is directly received by the light receiving element. It means a distance that is so short that it does not enter 22.

The reflected light R shown by the arrow in FIG. 3 is the reflected light R that is incident on the light receiving mirror 21 at an angle that is closest to the light receiving axis Rc from the light receiving mirror 21 toward the outside of the device among the reflected light R generated by the close-range object 50. Showing. The reflected light R shown in FIG. 3 does not enter the light receiving element 22 even if it is reflected by the light receiving mirror 21. Since the light receiving mirror 21 is designed to guide the reflected light R incident in parallel to the light receiving axis Rc to the light receiving element 22, the angle difference with respect to the light receiving axis Rc is further larger than that of the reflected light R shown in FIG. Even if the reflected light R is reflected by the light receiving mirror 21, it does not enter the light receiving element 22. From this, it can be seen that the reflected light R generated by the close-range object 50 does not enter the light receiving element 22 even if it is reflected by the light receiving mirror 21.

Even if the reflected light R is reflected by the light receiving mirror 21, the maximum value of the distance that does not enter the light receiving element 22 is a value determined by the structure of the laser radar device 1 such as the distance between the light receiving mirror 21 and the light projecting mirror 14.

As described above, the direct incident boundary line B represents an optical path that passes the closest to the light receiving mirror 21 when the reflected light R generated in the light projecting spot directly enters the light receiving element 22. Therefore, if the inner side surface 24b of the recess 24 is formed outside the light receiving field of the light receiving element 22 with respect to the direct incident boundary line B, the reflected light R generated by the close-range object 50 is directly at least slightly. , Enters the light receiving element 22.

In order to allow the light receiving element 22 to receive a larger amount of the reflected light R generated by the close-range object 50, the depth h1 of the concave portion 24, that is, the length from the upper bottom 24a of the concave portion to the opening of the concave portion 24 is set. It is preferable to make it as short as possible. However, the shallower the depth h1 of the recess 24 is, the more easily ambient light is directly incident on the light receiving element 22. In consideration of this, the depth of the recess 24 is designed.

Further, in order to allow the light receiving element 22 to receive a larger amount of the reflected light R generated by the close-range object 50, there is also a method of increasing the upper bottom 24a of the recess 24. However, the larger the upper base 24a, the easier the ambient light is to enter the light receiving element 22 directly. In consideration of this, the size of the upper bottom 24a of the recess 24 is also designed.

Further, of course, since it is necessary to prevent the support base 23 and the light receiving mirror 21 from coming into contact with each other, the depth h1 of the recess 24 also needs to be smaller than the height h2 from the light receiving element 22 to the tip of the light receiving mirror 21. is there.

[Summary of First Embodiment]
FIG. 4 shows the structure of the recess 124 as a comparative example. In the concave portion 124, the inner side surface 124b rises vertically from the upper bottom 124a. In this configuration, the direct incident boundary line B intersects with the portion forming the concave portion 124 of the support base 123. That is, the inner side surface 124b of the concave portion 124 is projected to the inside of the light receiving visual field from the direct incident boundary line B. Therefore, in the case of the comparative example, the reflected light R generated by the close-range object 50 cannot directly enter the light receiving element 22.

On the other hand, in the laser radar device 1 described above, the inner side surface 24b of the recess 24 is formed outside the light receiving field of the light receiving element 22 with respect to the direct incidence boundary line B. Therefore, the reflected light R generated by the close-range object 50 directly enters the light receiving element 22.

Further, while the inner side surface 24b of the concave portion 24 is located outside the light receiving field of the light receiving element 22 with respect to the direct incident boundary line B, the concave portion 24 is formed and is shielded by the side surface of the concave portion 24 to receive the light receiving element 22. Since some ambient light does not directly enter the light receiving element 22, the ambient light is also prevented from entering the light receiving element 22.

<Second Embodiment>
Next, a second embodiment will be described. In the following description of the second embodiment, elements having the same reference numerals as those used up to that point are the same as the elements having the same reference numerals in the previous embodiments, unless otherwise specified. Further, when only a part of the configuration is described, the above-described embodiment can be applied to the other part of the configuration.

In the first embodiment, the inner side surface 24b of the recess 24 has the same inclination over the entire range in the horizontal direction. On the other hand, in the second embodiment, as shown in FIG. 5, the inclination of the inner side surfaces 224b1 and 224b2 of the recess 224 differs depending on the direction in the horizontal plane.

FIG. 5 is a diagram showing the vicinity of the recess 224, and a state in which the support base 223 in which the recess 224 is formed is cut along a vertical cross section including the front direction of the laser radar device, similarly to FIG. Is shown in. Further, FIG. 6 is a view of the support base 223 viewed from the direction of arrow VI shown in FIG.

The recess 224 of the second embodiment includes an upper bottom 224a having the same size and shape as the upper bottom 24a of the first embodiment, and an inner side surface 224b having a different structure from the inner side surface 24b of the first embodiment.

The inner side surface 224b includes a front inner side surface 224b1 formed in a range of 180 degrees, which is an angle range in which the irradiation light L is scanned, and a rear inner side surface 224b2 formed in a remaining angle range in which the irradiation light L is not scanned. Equipped with.

The front inner side surface 224b1 has the same inclination as the inner side surface 24b of the first embodiment. On the other hand, the rear inner side surface 224b2 rises vertically from the upper bottom 224a, like the inner side surface 124b of the comparative example. The depth of the recess 224 is the same as that of the recess 24 of the first embodiment.

In the second embodiment, the front inner side surface 224b1 formed in the direction in which the irradiation light L is scanned is formed outside the light-receiving visual field with respect to the direct incident boundary line B, like the inner side surface 24b of the first embodiment. There is. On the other hand, the rear inner side surface 224b2 formed in the direction in which the irradiation light L does not scan rises vertically from the upper bottom 224a as in the comparative example.

Therefore, comparing the distance D1 from the opening side end point P4 of the rear inner side surface 224b2 to the light receiving axis Rc which is the central axis of the light receiving field, and the distance D2 from the opening side end point P5 of the front inner side surface 224b1 to the light receiving axis Rc. , The distance D1 is shorter. Therefore, the opening of the recess 224 of the second embodiment is smaller than the opening of the recess 24 of the first embodiment.

The ambient light may enter the recess 224 from various directions by being repeatedly reflected by various structures by the laser radar device. Since the opening of the recess 224 of the second embodiment is smaller than that of the recess 24 of the first embodiment, the disturbance light is prevented from entering the light receiving element 22 more than the recess 24 of the first embodiment. it can.

<Third Embodiment>
FIG. 7 is a diagram showing the vicinity of the recess 324 provided in the laser radar device of the third embodiment, and is a diagram corresponding to FIG. 5 of the second embodiment. The recess 324 of the third embodiment is formed in the support 323 and has the same size and shape as the upper bottom 24a of the first embodiment, and the inner side surface 24b of the first and second embodiments. , 224b, and an inner side surface 324b having a different structure.

Similar to the inner side surface 224b of the second embodiment, the inner side surface 324b is not scanned with the front inner side surface 324b1 formed in a range of 180 degrees which is an angular range in which the irradiation light L is scanned in the horizontal direction. And a rear inner side surface 324b2 formed in the remaining area.

The front inner side surface 324b1 has the same shape as the front inner side surface 224b1 of the second embodiment. The position of the opening side end point P4 of the rear inner side surface 324b2 is the same as that of the second embodiment, but has a concave surface shape that is recessed on the side opposite to the light receiving axis Rc. As shown in FIG. 7, the concave shape is designed to have a shape in which the reflected light R reflected by the close-range object 50 hits the rear inner side surface 324b2 and then is condensed in a range including the light receiving element 22. ing.

The reason why the concave shape can be designed in the above shape is as follows. By determining the distance to the short-distance object 50 that causes the reflected light R, the angle at which the reflected light R generated at the light projection spot enters the rear inner side surface 324b2 can be determined. From this angle and the known position of the light receiving element 22, how to make the concave shape of the rear inner side surface 324b2 collect the reflected light R incident on the rear inner side surface 324b2 in the range including the light receiving element 22. Whether to be illuminated can be designed in advance. -
Since the front inner side surface 324b1 is formed outside the light receiving visual field with respect to the direct incident boundary line B, a part of the reflected light R generated by the close-range object 50 directly enters the light receiving element 22. However, since the reflected light R is diffused light, a part of the remaining reflected light R enters the concave portion 324, but does not directly enter the light receiving element 22 and hits the rear inner side surface 324b2.

In the third embodiment, the reflected light R reflected by the close-range object 50 hits the rear inner side surface 324b2 and then is condensed in a range including the light receiving element 22. As a result, the efficiency with which the reflected light R that has entered the rear inner surface 324b2 enters the light-receiving element 22 can be increased. As a result, the detection sensitivity of the very close object 50 is improved.

Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and the following modifications are also included in the technical scope of the present invention. Various modifications can be made without departing from the scope.

<Modification 1>
Although the scanning range is 180 degrees in the above-described embodiment, the scanning range may be a range other than 180 degrees, such as 190 degrees and 360 degrees.

<Modification 2>
Further, when the scanning range is limited to a partial angular range in the horizontal plane, such as 180 degrees and 190 degrees, the range in which the front inner side surfaces 224b1, 324b1 are formed does not necessarily match the scanning range. You don't have to. The front inner side surfaces 224b1, 324b1 may be formed in a range wider than the scanning range, or the front inner side surfaces 224b1, 324b1 may be formed in a part of the scanning range.

<Modification 3>
In the above-described embodiment, the irradiation unit 10 is above the light receiving unit 20, but the relationship between the irradiation unit 10 and the light receiving unit 20 may be reversed, and the light receiving unit 20 may be arranged above the irradiation unit 10.

1: Non-coaxial laser radar device 2: Housing 2a: Rear surface 2b: Bottom surface 2c: Upper surface 3: Window 10: Irradiation portion 11: Light source 12: Driving portion 13: Lens 14: Light emitting mirror 15: Motor 20: Light receiving portion 21: light receiving mirror 22: light receiving element 23: support 24: recess 24a: upper bottom 24b: inner surface 30: comparator 40: control unit 50: close-up object 123: support 124: recess 124a: upper bottom 124b: inner surface 223: Support base 224: Recessed portion 224a: Upper bottom 224b: Inner side surface 224b1: Front inner side surface 224b2: Rear inner side surface 323: Support base 324: Recessed portion 324a: Upper bottom 324b: Inner side surface 324b1: Front inner side surface 324b2: Rear side Inner surface B: Direct incident boundary line L: Irradiation light Lc: Projection axis R: Reflection light Rc: Receiving axis

Claims (3)

A light source (11) for generating a laser beam,
A light projecting mirror (14) for deflecting the laser beam generated by the light source to project the laser beam to the outside and scanning the projecting direction;
A light receiving element (22) for receiving the reflected light generated by the laser light projected by the light projecting mirror being reflected by an external object;
A light receiving mirror (21) for deflecting the reflected light in the direction of the light receiving element ,
A window (3) through which the laser light projected by the projection mirror and the reflected light pass ,
The light receiving element is above the light receiving mirror,
A non-coaxial optical axis (Lc), which is the optical axis of the laser light projected to the outside, and a light receiving axis (Rc), which is the central axis of the light receiving field from the light receiving mirror to the outside, are different from each other. System laser radar device,
Separated from the reflected light reflected by the light receiving mirror, the light receiving mirror side is open, extends from the periphery of the light receiving element in the direction of the light receiving mirror, and surrounds the space on the light receiving mirror side of the light receiving element. A light shielding element (23, 223, 323) for suppressing the light from entering the light receiving element,
The shield, at least for part of the scan direction, the outer surface, remote from the window, and extends downwardly along said window, an inner surface (24b, 224b, 324b) is pre Me defined A direct incidence boundary that is a straight line connecting a point farthest from the light receiving element in a light projecting spot generated by irradiating the object located at a close range with the laser light and a point farthest from the light projecting spot in the light receiving element. A non-coaxial laser radar device formed outside the line of sight of the light receiving element with respect to the line (B). In claim 1,
The scanning range of the laser light is limited to a partial angular range in the horizontal plane,
The inner surface of the shield is formed outside the light-receiving visual field with respect to the direct incidence boundary line within the scanning range of the laser light, while at least a part of the outside of the scanning range of the laser light is formed. Regarding the range, the distance from the opening side end point of the inner side surface to the center axis of the light receiving field is the distance from the opening side end point of the inner side surface formed in the scanning range of the laser light to the center axis of the light receiving field. A non-coaxial laser radar device that is shorter than this. In claim 2,
Outside the scanning range of the laser light, the inner surface of the shield has a concave non-coaxial shape that collects the reflected light generated by an object located at the close range to a range including the light receiving element. Laser radar system.

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